Method and apparatus for transmitting and receiving UE capability information mobile communication system

ABSTRACT

In order to transmit capability information of a user equipment (UE) to an evolved Node B (eNB), the UE may generate a UE CAPABILITY INFORMATION message including the capability information of the UE, and transmit the generated UE CAPABILITY INFORMATION message to the eNB. Here, the capability information of the UE may include at least one band combination supported by the UE and whether Time Division Duplexing-Frequency Division Duplexing Carrier Aggregation (TDD-FDD CA) for the band combination is supported.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of prior application Ser.No. 15/595,362, filed on May 15, 2017, which issued as U.S. Pat. No.10,278,183 on Apr. 30, 2019; which is a continuation application ofprior application Ser. No. 14/707,205, filed on May 8, 2015, whichissued as U.S. Pat. No. 9,655,121 on May 16, 2017; and which claimedpriority under 35 U.S.C. 119(a) to applications filed in the KoreanIntellectual Property Office on May 9, 2014 and May 19, 2014, andassigned Serial Nos. 10-2014-0055917 and 10-2014-0059819, respectively,the entire contents of each of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method and an apparatus for reportinga capability of a user equipment in a mobile communication system, andmore particularly to a method and an apparatus for minimizing an amountof information reported when a capability of a user equipment isreported to a network.

2. Description of the Prior Art

Mobile communication systems have been developed for the purpose ofproviding communication while securing the mobility of a user. Themobile communication systems have reached the stage where a high speeddata communication service can be provided as well as voicecommunication on the strength of the rapid development of technologies.

Currently, a standardization operation of the 3rd Generation PartnershipProject (3GPP) regarding Long Term Evolution (LTE) system is beingprogressed as one of the next generation mobile communication systems.The LTE system is a technology which implements high speed packet basedcommunication having a transmission rate of a maximum of 100 Mbps fasterthan a data transmission rate of the conventional 3GPP system. Variousnew technologies are applied to the recent LTE communication systemswhile keeping pace with the completion of the LTE standardization, and adiscussion on LTE-Advanced (LTE-A) for significantly improving atransmission rate is regularized. Hereinafter, an LTE system refers toan existing LTE system and an LTE-A system.

A representative new technology employed to the LTE-A system is CarrierAggregation (CA). Carrier aggregation is a technology in which userequipment transmits and receives data using multi-carriers. Moreparticularly, the user equipment transmits and receives data throughplural aggregated carriers (generally carriers belonging to an identicalbase station). In the end, this is identical to a user equipmenttransmitting and receiving data through plural numbers of cells.

Technologies such as a Multiple Input Multiple Output (MIMO) and thelike, as well as the carrier aggregation have been employed to the LTE-Asystem.

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’. The 5G communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, an analog beam forming and large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud Radio Access Networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,Coordinated Multi-Points (COMP), reception-end interference cancellationand the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) andsliding window superposition coding (SWSC) as an advanced codingmodulation (ACM), and filter bank multi carrier (FBMC), non-orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA) as anadvanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof Things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofEverything (IoE), which is a combination of the technology and the BigData processing technology through connection with a cloud server, hasemerged. As technology elements, such as “sensing technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “security technology” have been demanded forIoT implementation, a sensor network, a Machine-to-Machine (M2M)communication, Machine Type Communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing Information Technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, Machine Type Communication (MTC), andMachine-to-Machine (M2M) communication may be implemented by beamforming, MIMO and array antennas. Application of a cloud Radio AccessNetwork (RAN) as the above-described Big Data processing technology mayalso be considered to be an example of convergence between the 5Gtechnology and the IoT technology.

SUMMARY OF THE INVENTION

As described above, as the new technologies are introduced into theLTE-A system, a method is required in which capability information onthe user equipment related to the technologies is efficiently reportedto a base station, so that the base station and the user equipmentefficiently perform mobile communication.

In accordance with an aspect of the present invention, there is provideda method of transmitting capability information of a User Equipment (UE)to an evolved Node B (eNB) by the UE, the method including: receiving afirst message including information that requests at least one frequencyband supported by the UE and at least one radio access capability of theUE from an evolved Node B, eNB; generating a second message includingcapability information of the UE; and transmitting the second message tothe eNB, wherein the capability information includes one or more carrieraggregation, CA, band combination supported by the UE wherein the atleast one CA band combination is requested in the first message andincludes two downlink frequency bands and one uplink frequency band.

In accordance with another aspect of the present invention, there isprovided a method of receiving capability information of a userequipment from a UE by an eNB, the method including: generating a firstmessage including information that requests at least one frequency bandsupported by a user equipment, UE, and at least one radio accesscapability of the UE; transmitting the first messageto the UE andreceiving a second message including capability information of the UEfrom the UE, wherein the capability information comprises at least onecarrier aggregation, CA, band combination supported by the UE, andwherein the at least one CA band combination is requested in the firstmessage and includes two downlink frequency bands and one uplinkfrequency band.

In accordance with another aspect of the present invention, there isprovided a UE for transmitting capability information of the UE to aneNB, the UE including: a transceiver that is configured to transmit andreceive signals to and from the eNB; and a controller that is configuredto generate to receive a first message including information thatrequests at least one frequency band supported by the UE and at leastone radio access capability of the UE from the eNB, to generate a secondmessage including capability information based on the first message, andto transmit the second message to the eNB, wherein the capabilityinformation comprises at least one carrier aggregation, CA, bandcombination supported by the UE, and wherein the at least one CA bandcombination is requested in the first message and includes two downlinkfrequency bands and one uplink frequency band.

In accordance with another aspect of the present invention, there isprovided an eNB for receiving capability information of a UE from theUE, the eNB including: a transceiver that is configured to transmit andreceive signals to and from the UE; and a controller configured togenerate a first message that requests at least one frequency bandsupported by the UE and at least one radio access capability of the UE,configured to transmit the first message to the UE, and configured toreceive, from the UE, a second message including capability informationcorresponding to the first message wherein the capability informationcomprises at least one carrier aggregation, CA, band combinationsupported by the UE, and wherein the at least one CA band combination isrequested in the first message and includes two downlink frequency bandsand one uplink frequency band.

In embodiments of the present invention, the capability informationfurther comprises at least one other CA band combination including twodownlink frequency bands and one uplink frequency band supported by theUE.

In embodiments of the present invention, the capability informationfurther comprises at least one non-CA band supported by the UE.

In embodiments of the present invention, CA band combinations in thecapability information, at least in part, are prioritized based on theinformation included in the first message.

In embodiments of the present invention, the second message furthercomprises information indicating at least one frequency band supportedby the UE.

In embodiments of the present invention, the capability informationfurther comprises at least one other CA band combination including twodownlink frequency bands and one uplink frequency band supported by theUE, and the capability information further comprises at least one non-CAband supported by the UE.

In embodiments of the present invention, the second message (alsoreferred to as capability information message or UE capabilityinformation message) only comprises part of the entire capability of theUE, wherein a capability including frequency bands at which the UE maycommunicate or frequency band combinations at which the frequency bandcombinations may communicate is defined as an entire capability of theUE. In embodiments of the present invention, said part of the entirecapability included in the second message is selected such that theentire capability can be determined by the eNB based on said parttransmitted by the second message. In embodiments of the presentinvention, said part of the entire capability included in the secondmessage is determined based on restriction information (also referred toas Capability report restriction information) included in the firstmessage.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptionin conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a structure of an LTE system to whichthe present invention is applied;

FIG. 2 is a diagram illustrating a structure of a wireless protocol inan LTE system to which the present invention is applied;

FIG. 3 is a diagram illustrating carrier aggregation in an LTE system towhich the present invention is applied;

FIG. 4 is a diagram illustrating an operation of an LTE system accordingto a first embodiment of the present invention;

FIGS. 5A to 5D are diagrams illustrating an example of capabilityinformation of a UE according to the first embodiment of the presentinvention;

FIG. 6 is a flowchart illustrating an operation of a UE according to thefirst embodiment of the present invention;

FIG. 7 is a diagram illustrating an operation of an LTE system accordingto a second embodiment of the present invention;

FIG. 8 is a diagram illustrating an example of capability reportrestriction information of a UE according to the second embodiment ofthe present invention;

FIG. 9 is a flowchart illustrating an operation of a UE according to thesecond embodiment of the present invention;

FIG. 10 is a block diagram illustrating a configuration of a UEaccording to an embodiment of the present invention; and

FIG. 11 is a block diagram illustrating a configuration of a basestation according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.Further, in the following description of the present invention, adetailed description of known functions and configurations incorporatedherein will be omitted when it where the detailed description isconsidered not increasing the intellegibility of the subject matter ofthe present invention. The terms which will be described below are termsdefined in consideration of the functions in the present disclosure, andmay be different according to users, intentions of the users, orcustoms. Therefore, the terms should be determined based on thedefinitions provided in the description with due regard to thedescription as a whole.

FIG. 1 is a view illustrating a structure of an LTE system to which thepresent invention is applied. Although an LTE system will be describedas an example of a mobile communication system to which the presentinvention may be applied, the present invention is not limited to such aspecific system.

Referring to FIG. 1, a wireless access network of the mobilecommunication system includes evolved Node Bs (hereinafter, referred toas eNBs, Node Bs, or base stations) 105, 110, 115 and 120, a MobilityManagement Entity (MME) 125, and a Serving-Gateway (S-GW) 130. A UE(hereinafter, referred to as a UE or a terminal) 135 accesses anexternal network (not illustrated) through the eNBs 105, 110, 115, and120 and the S-GW 130.

The eNBs 105, 110, 115 or 120 corresponds to an existing node B in aUniversal Mobile Telecommunication System (UMTS). The eNBs are connectedwith the UE 135 through a wireless channel, and each eNB performs a morecomplicated function than that of the existing node B. In the LTEsystem, because all user traffic including a real time service, forinstance through an Internet Protocol (IP) such as a Voice over IP(VoIP), are serviced through a shared channel, an apparatus forcollecting and scheduling state information on buffering states of theUEs, a state of available transmission electric power, a channel stateand the like is required, and, the eNBs 105, 110, 115 and 120 areresponsible for these functions. One eNB generally controls a pluralityof cells.

In order to implement a high transmission rate, the LTE system employsOrthogonal Frequency Division Multiplexing (hereinafter, referred to asOFDM) in a 20 MHz bandwidth as a wireless access technology.Furthermore, Adaptive Modulation & Coding (hereinafter, referred to asAMC) through which a modulation scheme and a channel coding rate aredetermined according to a channel state of the UE is applied.

The S-GW 130 is a device that provides a data bearer, and generates orremoves the data bearer under the control of the MME 125. The MME 125 isa device that is responsible for various control functions as well as amobility management function for the UE, and is connected with aplurality of the eNBs 105, 110, 115 and 120.

FIG. 2 is a view illustrating a structure of a wireless protocol in theLTE system to which the present invention is applied.

Referring to FIG. 2, the UE and the eNB include a Packet DataConvergence Protocol (PDCP) 205 or 240, a Radio Link Control (RLC) 210or 235 and a Medium Access Control (MAC) 215 or 230, respectively, asthe wireless protocol of the LTE system. The PDCPs 205 and 240 areresponsible for operations such as compression and restoration of IPheaders, and the RLCs 210 and 235 perform an Automatic RetransmissionRequest (ARQ) operation and the like by reconfiguring a Packet Data Unitor Protocol Data Unit (PDCP or PDU) into a suitable size. The MAC 215 or230 is connected with various RLC layer devices configured in one UE,and performs an operation of multiplexing RLC PDUs to MAC PDU anddemultiplexing the RLC PDUs from the MAC PDU.

A physical layer 220 or 225 channel-codes and modulates higher layerdata, generates an OFDM symbol to transmit the OFDM through a radiochannel, or is responsible for an operation of demodulating andchannel-decoding the OFDM symbol received through the radio channel andto transmit the channel-decoded OFDM symbol to the higher layer, andperforms a Hybrid ARQ (HARQ) operation for transmitting and receivingdata. In order to support transmission of uplink data, the physicallayer 220 or 225 manages a Physical Uplink Shared Channel (PUSCH), aPhysical HARQ Indicator Channel (PHICH) that transfers anAcknowledgement (ACK)/Non-Acknowledgement (NACK) corresponding to anHARQ feedback for transmission of a PUSCH, a Physical Downlink ControlChannel (PDCCH) that transfers a downlink control signal (for example,scheduling information), and a Physical Uplink Control Channel (PUCCH)that transfers an uplink control signal. The physical layer 220 or 225may manage the Physical Downlink Shared Channel (PDSCH) in order tosupport transmission of downlink data.

FIG. 3 is a diagram illustrating carrier aggregation in an LTE system towhich the present invention is applied.

Referring to FIG. 3, one eNB generally transmits and receives multiplecarriers through various frequency bandwidths. For example, when an eNB305 transmits a carrier 315, the central frequency of which is f1, and acarrier 310, the central frequency of which is f3, a UE that does nothave carrier aggregation capability can transmit and receive data usingone of the two carriers 310 and 315. However, a UE 330 having carrieraggregation capability can simultaneously transmit and receive datato/from different carriers 310 and 315. The eNB 305 may allocate morecarriers to the UE 330 having the carrier aggregation capabilityaccording to circumstances, and then can improve the transmission rateof the UE 330.

It may be understood that the carrier aggregation means that a UEsimultaneously transmits and receives data through several cells whenone downlink carrier and one uplink carrier which are transmitted andreceived by one eNB constitute one cell. A maximum data transmissionrate increases in proportion to the number of aggregated carriers.

Hereinafter, in the following description of the embodiments of thepresent disclosure, the reception of the data through the downlinkcarrier or the transmission of the data through the uplink carrier inthe UE has the same meaning as the transmission and reception of thedata by using a control channel and a data channel which are provided bya cell corresponding to a center frequency and a frequency band whichspecify the carrier. In the description, ‘Carrier Aggregation (CA)’means that a plurality of serving cells is set in one UE. Hereinafter,an LTE system will be described as an example of the present disclosurefor convenience of the description, but the embodiments of the presentdisclosure may be applicable to all kinds of wireless communicationsystems supporting the carrier aggregation.

In recent years, a TDD-FDD CA function for aggregating a TDD servingcell and an FDD serving cell have become necessary. The carrieraggregation between the two different duplex modes is a significantlyuseful function to service providers equipped with both a TDD frequencyband and an FDD frequency band, and the number of such providers tendsto increase gradually.

A primary cell (PCell) and a secondary cell (SCell) are set in a UE towhich carrier aggregation is applied. While the UE and the eNB transmitvarious uplink control signals (an HARQ feedback, Channel StateInformation (CSI), and an Scheduling Request (SR) signal) through thePUCCH and maintain a state in which data can be always transmitted andreceived, the SCell transmits and receives data through the PDSCH andthe PUSCH, but the PUCCH is not transmitted but is transited between anenable state and a disable state according to an instruction of the eNB.

In the FDD mode, the HARQ feedback for a PDSCH received from apredetermined sub frame N is transmitted from a sub frame N+4 throughthe PUCCH of the PCell. In the TDD mode, the HARQ feedback for a PDSCHreceived from a predetermined sub frame N is transmitted from a subframe N+k through the PUCCH of the PCell. The k is a value determinedaccording to TDD UL/DL setting, and is defined in Standard 3GPP TS36.213.

If the PCell of a UE in which the TDD-FDD CA is set is operated in theFDD mode, there is no difficulty in transmitting a HARQ feedback becausethe PUCCH is present in all sub frames for transmitting an HARQ feedbackfor the PDSCH received by the TDD SCell to the FDD PCell. Meanwhile, ifthe PCell is operated in the TDD mode, an original HARQ feedback timingcannot be achieved because the PUCCH is present by only some sub framesdue to the attribute of the TDD in transmitting an HARQ feedback for aPDSCH received from the FDD SCell to the TDD PCell. In the case of theTDD PCell, it is necessary to correct an HARQ feedback timing, whichmeans that a new function should be added to a modem of the UE.

In order for the UE to properly operate in a given communicationnetwork, information (hereinafter, capability information) related tothe capability of the UE should be provided to the network (or at leastone specific network node). The capability information may include, forexample, information on which feature and frequency the UE supports. Asthe capability of the UE is advanced and a new function such as carrieraggregation is introduced, complexity and magnitude of the capabilityinformation of the UE also increases.

In order to report whether TDD-FDD CA will be supported in a network byan arbitrary UE, the following three types of information elements arenecessary:

-   -   Which band combination supports TDD-FDD CA?    -   Is a FDD PCell supported?    -   Is a TDD PCell supported?

In an embodiment, the present invention suggests a method of signalingthe first type of information elements for each band combination, andsignaling the second and third types of information elements(hereinafter, a PCell mode capability) for each UE. That is, in onecapability report control message, a plurality of first type ofinformation elements are signaled and only one second type ofinformation element and one third type of information element aresignaled.

In embodiments of the present invention, the UE reports information onbands supported by the UE and a combination of the bands and definesidentifiers for the bands such that the identifiers do not overlap eachother for the FDD band and the TDD band (for example, when a bandcorresponding to frequency bands f1 and f2 is used for the TDD in area Aand is used for the FDD in area B, one band indicator for the frequencyband is defined for the TDD and one band indicator for the frequencyband is defined for the FDD), and thus indicates whether the UE supportsthe TDD-FDD CA for each combination of bands with reference to the bandindicators of the frequency bands reported by the UE. For example, whenit is assumed that frequency band indictors 0 to 31 relate to an FDDband and frequency band indicators 32 to 63 relate to a TDD band, the UEsupports the TDD-FDD CA for the combination of bands if the UE reportsthat it supports a combination of band 1 and band 50.

One UE may support the TDD-FDD CA in a plurality of band combinations.Then, although it is not impossible to design the UE such that PCellmode capability (a capability on which duplex mode is supported by theUE in the PCell) may vary for the band combinations, a loss due to anincrease in the complexity of the UE is more severe than a gain due toflexibility. According to embodiments of the present invention, the UEapplies the same PCell mode capability for all band combinationssupported by the TDD-FDD CA, and information regarding the fact issignaled using one frequency band combination regardless of the numberof frequency band combinations that support the TDD-FDD CA.

The following are capability information elements that should bereported to a network by a UE supporting carrier aggregation:

-   -   Frequency band(s) supported by the UE    -   Combination(s) of frequency bands supported by the UE    -   The number of cells that may be aggregated for frequency bands    -   Maximum bandwidths for frequency bands

The information elements may be mutually combined to express ameaningful capability. For example, the UE reports the followingcapability information to the network:

-   -   aggregating two cells throughout a bandwidth of maximum 20 MHz        as a downlink while aggregating two cells throughout a bandwidth        of maximum 20 MHz as an uplink in band 1;    -   aggregating one cell throughout a bandwidth of maximum 10 MHz as        an uplink while aggregating two cells throughout a bandwidth of        maximum 20 MHz as a downlink in band 1;    -   aggregating two cells throughout a bandwidth of maximum 20 MHz        as a downlink while aggregating one cell throughout a bandwidth        of maximum 10 MHz as an uplink in band 1, and aggregating two        cells throughout a bandwidth of maximum 20 MHz as a downlink        while aggregating two cells throughout maximum 20 MHz as an        uplink in band 2; and the like.

The simplest method of reporting the capability information to thenetwork is to explicitly report the information elements one by one.However, because the UE tends to support a larger number of bandcombinations due to the introduction of new features such as carrieraggregation, the size of the capability information abruptly increasesin the above-mentioned report method as the number of band combinationsincreases. In order to efficiently and accurately report the capabilityof the UE, the capability information of the UE is preferablyabbreviated and reported. To achieve this, the following suggestion maybe introduced.

The added bandwidth and the maximum number of cells may be expressedtogether using a parameter called Bandwidth Class (BWC). As an example,the bandwidth classes may be defined as in Table 1.

TABLE 1 Maximum number of CA Bandwidth Aggregated Transmission ComponentClass Bandwidth Configuration Carrier (CC) A Added bandwidth = 20 MHz 1B Added bandwidth = 20 MHz 2 C 20 MHz < Added bandwidth ≤ 40 2 MHz

For example, the fact that a bandwidth class for a certain frequencyband is A means that a maximum of one carrier (or one serving cell) maybe set for the frequency band and the total sum of the bandwidths of theserving cells set in the frequency band is a maximum of 20 MHz.

When two or more bandwidth classes are supported in any one frequencyband in a frequency band combination, they may be included in the sameInformation Element (hereinafter, IE). Then, frequency band combinationinformation should be configured such that all combinations of thebandwidth classes recorded in one frequency band combination aresupported by a terminal.

First Embodiment

FIG. 4 is a diagram illustrating an operation of an LTE system accordingto a first embodiment of the present invention.

A UE is powered, in step 420, on in a mobile communication systemincluding the UE 405, an eNB 410, and an MME 415. The UE searches for acell that receives electric waves and a PLMN through a cell searchprocess, and determines, in step 425, through which cell of a PLMN aregistration process will be performed based on the search result.

After performing an Radio Resource Control (RRC) connection settingprocess through the selected cell, the UE transmits, in step 430, acontrol message ATTACH REQUEST that requests registration to the MME.The message includes information such as an identifier of the UE. Afterthe MME determines whether registration of the UE will be allowed if anATTACH REQUEST message is received, and if it is determined that theregistration will be allowed, the MME transmits, in step 435, a controlmessage called an Initial Context Setup Request Message to a serving eNBof the UE. If the MME has capability information of the UE, the messageis transmitted while containing capability related information of theUE, but because the MME does not have such information in the initialregistration process, the message does not contain UE capability relatedinformation. If receiving an Initial Context Setup Request Message thatdoes not include capability information of the UE, the eNB transmits, instep 440, a control message called UE CAPABILITY ENQUIRY to the UE. Themessage instructs the UE to report capability, and requests capabilityinformation for a specific Radio Access Technology (RAT) of the UE usinga parameter called RAT Type. If the UE performs the process in an LTEnetwork, the RAT-Type is set to an Evolved Universal Terrestrial RadioAccess (EUTRA). The eNB also may request Universal MobileTelecommunications System (UMTS) related capability information of theUE by adding the UTRA to the RAT-Type for provision against a handoverif another wireless network, for example, a UMTS network is presentaround the eNB. If receiving a UE CAPABILITY ENQUIRY control message,the UE generates UE CAPABILITY INFORMATION in which capabilityinformation of the UE for a wireless technology instructed by the RATType is recorded. The UE CAPABILITY INFORMATION may include one or moreband combination information elements for the band combinationssupported by the UE. The band combination information elements areinformation elements that represent which CA combination is supported,and the eNB may set a suitable CA in the UE using the band combinationinformation elements. The UE CAPABILITY INFORMATION also may includeinformation related to a TDD-FDD CA capability of the UE. The UEtransmits, in step 445, the UE CAPABILITY INFORMATION message to theeNB. The eNB transmits, in step 450, a UE CAPABILITY INFO INDICATIONmessage to the MME to report capability information of the UE recordedin the UE CAPABILITY INFORMATION message. The eNB also may properlyreset the UE with reference to a traffic situation and a channelsituation of the UE based on capability information reported by the UE.For example, the eNB may set, in step 455, an additional SCell in the UEthrough an RRC CONNECTION RECONFIGURATION message or set a measurementgap while instructing measurement for another frequency to the UE.

In step 460, the eNB and the UE transmit and receive data by applyingthe setting.

FIGS. 5A to 5D are diagrams illustrating capability informationaccording to a first embodiment of the present invention.

Referring to FIGS. 5A to 5D, the capability information of the UEincludes an E-UTRA band information (SupportedBandListEUTRA) 501,information 508 on a band combination supported by the UE, a measurementcapability parameter (MeasParameter) 535 of the UE, PCell mode relatedinformation (PCellCapability) 530 of the UE, and release information(accessStratumRelease) 507 of the UE.

The release information 507 of the UE in FIG. 5A is informationregarding which release of the LTE standards is realized in the UE.

FIG. 5B includes information on an EUTRA band supported by the UE, forexample, frequency band indicators 503 and 505. It is assumed that theUE supports band X and band Y, which are an FDD band and a TDD band,respectively.

In FIG. 5C, SupportedBandCombinationList includes one or more bandcombination parameters (BandCombinationParameters, BCPs hereeafter) 510,515, 520, and 525. The BCP is information on band combinations supportedby the UE. The BCP includes one or more band parameters (BandParameters,BPs hereafter). The BP includes a band indicator (FreqBandIndicator), aforward band parameter (bandParametersDL, BPDL hereinafter), and areverse band parameter (bandParametersUL, BPUL hereinafter). The BPDLincludes a bandwidth class (bandwidthClass) that indicates the number ofserving cells supported by the corresponding band and antenna capabilityinformation. For example, bandwidth class A may represent a capabilityby which one serving cell of a maximum entire bandwidth of 20 MHz may beset, bandwidth class B may represent a capability by which two servingcells may be set and a total entire bandwidth is a maximum of 20 MHz,and bandwidth class C may represent a capability by which two servingcells may be set and a total entire bandwidth is a maximum of 40 MHz.

In 525 of FIG. 5C, the UE supports CA in a combination of band X andband Y. Then, band X is an FDD band and band Y is a TDD band, the UE isa UE that supports TDD-FDD CA.

As described above, the UE that supports TDD-FDD CA in at least one bandcombination includes two or more entries 527 and 528 and PCellCapability530 information into the capability report message. The PCellCapabilityinformation is information regarding in which mode PCell is supportedand may include one or two information elements, which will be describedin the following.

In the following an example is described in which PCellCapabilityincludes one information element.

All UEs that support TDD-FDD CA in the at least one band combinationsupport [FDD PCell, TDD SCell], and PCellCapability represents onlywhether [TDD PCell, FDD SCell] are supported.

If the information indicates Yes, it means that the UE supports [TDDPCell, FDD SCell] and [FDD PCell, TDD SCell] in all band combinationsthat have been reported to support TDD-FDD CA.

If the information is not included or the information indicates No, itmeans that the terminal does not support [FDD PCell, TDD SCell] in anyof the band combinations that have been reported to support TDD-FDD CA.

[TDD PCell, FDD SCell] is set such that PCell is a TDD serving cell andat least one SCell is an FDD serving cell.

[FDD PCell, TDD SCell] is set such that PCell is a FDD serving cell andat least one SCell is an TDD serving cell.

Now an example is described in which PCellCapability includes twoinformation elements.

The first information element represents whether the UE supports [TDDPCell, FDD SCell], and the second information element represents whetherthe UE supports [FDD PCell, TDD SCell].

If the first information indicates Yes, it means that the UE supports[TDD PCell, FDD SCell] in all band combinations that have been reportedto support TDD-FDD CA.

If the first information is not included or the first informationindicates No, it means that the terminal does not support [TDD PCell,FDD SCell] in any of the band combinations that have been reported tosupport TDD-FDD CA.

If the second information indicates Yes, it means that the UE supports[FDD PCell, TDD SCell] in all band combinations that have been reportedto support TDD-FDD CA.

If the second information is not included or the second informationindicates No, it means that the terminal does not support [FDD PCell,TDD SCell] in any of the band combinations that have been reported tosupport TDD-FDD CA.

When PCellCapability includes one information element, the capabilityreport information reported by the UE may be analyzed as in Table 2.Accordingly, the UE may configure UE capability report informationaccording to the contents of Table 2.

TABLE 2 SupportedBandCombinationList PCellCapability UE capability Case1 All the band combinations Not present UE that does not correspondingto CA relate to FDD- support TDD-FDD FDD CA (all band indicators of theCA band combinations are FDD band indicators) or relate to TDD-TDD CA(all band indicators of the band combinations are TDD band indicators).Case 2 At least one of the band Not present or Supports TDD-FDDcombinations corresponding to CA No CA, and all band relates to TDD-FDDCA (at least one combinations of the band indicators of the bandsupporting TDD-FDD combinations is an FDD band CA support [FDD indicatorand at least one of them is a PCell, TDD SCell]. TDD band indicator).Case 3 Identical with Case 2 Present or Yes Supports TDD-FDD CA, and allband combinations supporting TDD- FDD CA support [FDD PCell, TDD SCell]and [TDD PCell, FDD SCell].

When PCellCapability includes two information elements, the capabilityreport information reported by the UE is analyzed as in Table 3.Accordingly, the UE may configure UE capability report informationaccording to the contents of Table 3.

TABLE 3 PCellCapability PCellCapability on [FDD PCell, on [TDD PCell,SupportedBandCombinationList TDD SCell] FDD SCell] UE capability Case 4Identical with Case 1 Not present Not present UE that does not supportTDD-FDD CA Case 5 Identical with Case 2 Not present or Present or YesSupports TDD-FDD CA, No and all band combinations supporting TDD-FDD CAsupport [TDD PCell, FDD SCell]. Case 6 Identical with Case 2 Present orYes Not present or Supports TDD-FDD CA, No and all band combinationssupporting TDD-FDD CA support [FDD PCell, TDD SCell]. Case 7 Identicalwith Case 2 Present or Yes Present or Yes Supports TDD-FDD CA, and allband combinations supporting TDD-FDD CA support [FDD PCell, TDD SCell]and [TDD PCell, FDD SCell]. Case 8 Identical with Case 2 Not present orNot present or UE capability in Case 8 is No No described below thistable.

The following is a description of UE capability in Case 8.

This is the case in which the UE supports TDD-FDD CA in at least oneband combination and PCellCapability is not included in capabilityinformation.

Because PCellCapability is a parameter introduced from a specificrelease (for example, Release 12), the UE (for example, the Release 10terminal) which functions according to a lower release cannot use theparameter. However, considerable demand for TDD-FDD CA exists for the UEbefore the specific release. Accordingly, according to an embodiment ofthe present invention, when the UE functioning in a lower than thespecific release reports that at least one band combination supportsTDD-FDD CA and does not report PCellCapability, the UE supports [FDDPCell, TDD SCell]. Accordingly, in one of the UEs before the specificrelease that supports TDD-FDD CA in at least one band combination, aband combination that supports the TDD-FDD CA is included inSupportedBandCombinationList if the band combination supports [FDDPCell, TDD SCell], and the TDD-FDD CA is not included inSupportedBandCombinationList otherwise.

The UEs corresponding to the specific release and the releases after thespecific release include PCellCapability if the at least one bandcombination supports TDD-FDD CA.

Accordingly, if the UE that has reported that the at least one bandcombination supports TDD-FDD CA does not report PCellCapability, the eNBidentifies the release information of the UE, if the release correspondsto a release prior to the specific release, it is determined that the UEsupports TDD-FDD CA, and the release corresponds to the specific releaseor a release after the specific release, it is determined that the UEdoes not support TDD-FDD CA.

An Inter-Operability Test (IOT) is an associated test between a UE and anetwork, and it is preferable that only a function is to be used thathas passed through the associated test. Because the IOT requires both acommercially realized UE and a network, the IOT may not be performedeven if the UE implements the function in the step in which an arbitraryfunction is not widely implemented. In particular, when a network is notpresent that actually uses a band combination for applying TDD-FDD CA oronly a network exists which supports either FDD PCell or TDD PCell, itis impossible to perfectly perform the IOT), and the IOT may beperformed only for one of FDD and TDD in the band combination even ifthe UE supports both the FDD PCell and TDD PCell. Accordingly, if the UEdoes not separately report an IOT situation for PCellCapability, amultiple connection operation may be limitedly applied because the eNBcannot be sure for which PCell mode the IOT is performed. Accordingly,the UE may include information regarding for which PCellCapability theIOT is completed for TDD-FDD CA band combinations. In particular, theinformation may be realized to report only the UE that supports both FDDPCell and TDD PCell. The UE that supports only one of two functions (forexample, FDD PCell) omits BandCombinationParameters corresponding to theband combination from the capability information to indirectly displaythat the IOT is not performed if the IOT for the function is notperformed in BandCombinationParameters (that includes two or more bandentries, in which at least one band entry is indicated by a bandindicator pertaining to a first area and at least one band entry isindicated by a band indicator pertaining to a second area) for anarbitrary TDD-FDD CA band combination.

Whether the IOT is performed may be individually reported for FDD PCelland TDD PCell or may be integrated into one information element to bereported, and the UE supports TDD-FDD CA in a predetermined bandcombination due to an RF capability of the UE and includesBandCombinationParameters for the band combination in the capabilityinformation only when the IOT for at least one of FDD PCell and TDDPCell is completed in the band combination.

Table 4 illustrates an example of capability information individuallyreporting whether the IOT is performed for FDD PCell and TDD PCell. InTable 4, the UE reports BandCombinationParameters for six bandcombinations, and reports IOT related information only for twoBandCombinationParameters related to TDD-FDD CA.

TABLE 4 FDD PCell IOT Bandcombina- related TDD PCell IOT tionParametersinformation related information Others Band Band 1 Not present Notpresent Not TDD-FDD CA combination 1 Band Band 2 Not present Not presentNot TDD-FDD CA combination 2 Band Band 50 Not present Not present NotTDD-FDD CA combination 3 Band Band 1 + Not present Not present NotTDD-FDD CA combination 4 Band 2 Band Band 2 + Yes No Perform IOT forcombination 5 Band 50 FDD PCell Not perform IOT for TDD PCell Band Band1 + Yes Yes Perform IOT for combination 6 Band 50 FDD PCell Perform IOTfor TDD PCell

In Table 4, for example, the fact that the IOT is performed for FDDPCell in band combination 5 means that TDD-FDD CA is possible for FDDPCell in the corresponding band combination.

Table 4 individually displays whether the IOTs for FDD PCell and TDDPCell are performed. Alternatively, whether the IOT for FDD PCell isperformed is associated with presence of the corresponding bandcombination, and only whether the IOT for TDD PCell is performed may beindividually displayed. For example, the fact that the IOT informationfor the TDD-FDD CA band combination is Yes means that both the IOTs forFDD PCell and TDD PCell are performed for the corresponding bandcombination, and if the IOT information for another TDD-FDD CA bandcombination is No, it means that only the IOT for FDD PCell is performedfor the corresponding band combination.

The display of the IOT being Yes or No may be indicated by 1 bitinformation. Alternatively, it may be indicated by presence or absenceof the corresponding information. For example, if the correspondinginformation is present, it may indicate Yes, and if the correspondinginformation is not present, it may indicate No.

FIG. 6 is a flowchart illustrating an operation of a UE according to thefirst embodiment of the present invention.

Referring to FIG. 6, in step 605, when receiving the UE CAPABILITYENQUIRY control message, the UE performs step 610 and identifies the RATType included in the message.

If the RAT Type is set to EUTRA, the UE performs step 620, while if theRAT Type is not set to the EUTRA but another value, the UE performs step615. In step 615, the UE performs an operation of reporting a capabilityfor the corresponding RAT according to the related art that is describedin Standard 3GPP TS 36.331. In step 620, as described above, the UE maygenerate performance information of the UE. The performance informationmay include SupportedBandList coded into ASN.1,SupportedBandCombinationList, or PCellCapability information, and the UEmay set the capability information in consideration of whether TDD-FDDCA is supported or the release or PCell mode capability of the UE.

In step 625, the UE generates a UE CAPABILITY INFORMATION messagecontaining the capability information and transmits the generated UECAPABILITY INFORMATION message to the eNB. Then, if the user data (forexample, an IP packet or a voice frame) that were generated first arepresent, the UE CAPABILITY INFORMATION message may be transmitted aheadof the user data that were generated first.

Second Embodiment

The UE reports all bands and band combinations supported by the UE toSupportedBandCombinationList. The amount of reported information is notlarge when the number of bands supported by the UE is small, but as thenumbers of bands and band combinations supported by the UE increase, thesize of SupportedBandCombinationList may also exponentially increase.

According to the present invention, the problem is solved by reportingonly information on a capability required by the eNB.

FIG. 7 is a diagram illustrating an operation of an LTE system accordingto a second embodiment of the present invention.

Like in steps 420 to 435 of FIG. 4, after steps 720 to 735 areperformed, the eNB transmits a control message called UE CAPABILITYENQUIRY to the UE in step 740. The control message may further includecapability report restriction information that indicates that only apredetermined capability will be reported in order to restrict the sizeof UE CAPABILITY INFORMATION.

Provided is a first example of capability report restriction information(hereinafter, Capability report restriction information 1).

In the eNB, or a mobile communication network that currently provides aservice to the UE, capability report restriction information 1 isinformation that indicates that capability information related to anactually used frequency band and includes an E-UTRA frequency list.

Further it is provided a second example of capability report restrictioninformation (hereinafter, Capability report restriction information 2).

In the eNB, or a mobile communication network that currently provides aservice to the UE, capability report restriction information 2 isinformation that indicates that capability information related to anactually used frequency band combination and includes an E-UTRAfrequency band combination list.

Yet further it is provided a third example of capability reportrestriction information (hereinafter, Capability report restrictioninformation 3).

In the eNB, or a mobile communication network that currently provides aservice to the UE, capability report restriction information 3 isinformation that indicates that capability information related to anactually used frequency band combination and a bandwidth class andincludes an E-UTRA frequency band combination list and a highestbandwidth class supported by the current network.

Even yet further it is provided a fourth example 4 of capability reportrestriction information (hereinafter, Capability report restrictioninformation 4).

In an eNB or a mobile communication network currently serviced by an UE,an E-UTRA frequency band combination list and a type of the frequencyband combination (or the number of configurations) are configured asinformation that indicates that only capability information related to afrequency band combination of a specific type (or configured with aspecific number of frequency band combinations) of a frequency bandcombination of the frequency band combinations that may be actuallyused.

In the present invention, a capability including frequency bands atwhich the UE may communicate or frequency band combinations at which thefrequency band combinations may communicate is defined as an entirecapability of the UE. In step 745, a UE CAPABILITY INFORMATION messagethat reports only some capabilities of the entire capability of the UEaccording to the capability report restriction information may betransmitted to the eNB. Then, the UE may include information such thatonly some capabilities are reported in UE CAPABILITY INFORMATION.Alternatively, the UE may report the entire capability of the UEregardless of the capability report restriction information. Then, theUE may include information such that the entire capability is reportedin UE CAPABILITY INFORMATION. Alternatively, the eNB may be informed ofa fact that the UE reports an entire capability by excluding informationregarding the fact that some capabilities are reported from UECAPABILITY INFORMATION.

When the UE reports some capabilities of the entire capability accordingto the capability report restriction information, the UE selects somecapabilities that will be reported as follows.

<When Capability Report Restriction Information 1 is Used>

SupportedBandListEUTRA: includes all E-UTRA bands supported by the UE.

SupportedBandCombinationList: a band combination including one band (ora band entry) of band combinations supported by the UE includes allE-UTRA bands supported by the UE, and a band combination including twoor more bands (or band entries) includes only a band combinationassociated with the bands indicated by capability report restrictioninformation 1.

MeasParamters: includes only the remaining measurement capabilityinformation other than measurement capability information related to aband combination excluded by capability report restriction information 1of the entire measurement capability information of the UE.

Capability report restriction information 1 is not applied for a bandcombination including one band in SupportedBandCombinationList becausethe band combination is applied not to a CA operation but to a generaloperation (non-CA band) so that it may be necessary when a handover toanother communication network is performed later, and the number of bandcombinations including one band is restrictive so that the number of thesizes of the messages is mere even if the all the band combinations areincluded.

<When Capability Report Restriction Information 2 is Used>

SupportedBandListEUTRA: includes all E-UTRA bands supported by the UE.

SupportedBandCombinationList: a band combination including one band (ora band entry) of band combinations supported by the UE includes allE-UTRA bands supported by the UE, and a band combination including twoor more bands (or band entries) includes only a band combinationindicted by capability report restriction information 2.

MeasParamters: includes only the remaining measurement capabilityinformation other than measurement capability information related to aband combination excluded by capability report restriction information 2of the entire measurement capability information of the UE.

<When Capability Report Restriction Information 3 is Used>

SupportedBandListEUTRA: includes all E-UTRA bands supported by the UE.

SupportedBandCombinationList: a band combination including one band (ora band entry) of band combinations supported by the UE includes allE-UTRA bands supported by the UE, and a band combination including twoor more bands (or band entries) includes only the remaining bandcombinations other than band combinations indicted by capability reportrestriction information 3.

MeasParamters: reports only the remaining measurement capabilityinformation other than measurement capability information related to aband combination excluded by capability report restriction information 3of the entire measurement capability information of the UE.

<When Capability Report Restriction Information 4 is Used>

SupportedBandListEUTRA: includes all E-UTRA bands supported by the UE.

SupportedBandCombinationList: The band combinations of the bandcombinations supported by the UE, which is indicated by capabilityreport restriction information 4, also include only band combinationscorresponding to the indicated specific type (or corresponding to theindicated specific number). Then, band combinations including one band(or band entry) or carrier aggregated band combinations including twodownlinks band and one uplink band may be included regardless of theindicated information. That is, parts of the band combinations may beincluded in the indicated information and the rest of the bandcombinations may be not included in the indicated information.

In FIG. 5D, the MeasParameters (535) is information related to themeasurement capability of the UE. The measurement capability parametersinclude band information elements (BandInfoEUTRAs) (hereinafter, BIs)540, 542, 544, and 546 corresponding the number of the BCPs 510, 515,520, and 525, and the BIs correspond to the BCPs according to thesequence in which the BCPs and the corresponding information elementsare recorded. That is, the BI 540 corresponds to the BCP 510, and the BI542 corresponds to the BCP 515. The BI includes interFreqBandList(hereinafter, IFBL) that is information regarding whether a measurementgap is necessary when an inter-frequency measurement is performed forfrequency bands and interRAT-BandList (hereinafter, IRBL) that isinformation regarding whether a measurement gap is necessary whenfrequency bands of other Radio Access Technologies (RATs) (for example,UTRAs) are measured. The IFBL includes Measurement Gap Need for Gaps(hereinafter, IFNGs) corresponding to the number of EUTRA frequencybands supported by the UE. The IFNG displays whether a measurement gapis necessary in the sequence for EUTRA frequency bands recorded in thesupported EUTRA frequency band list (supportedBandListEUTRA). If the UErecords band X and band Y in supportedBandListEUTRA, the first IFNG 550represents a measurement gap needed for band X and the second IFNG 555represents a measurement gap needed for band Y. That is, the IFNG 550represents whether a measurement gap is necessary when the UE performsan inter-frequency measurement for band X in the case where the UE isset according to the BCP 510, and the IFNG 555 represents whether ameasurement gap is necessary when an inter-frequency measurement isperformed for band Y.

The frequency band reported in supportedBandListEUTRA should be reportedas band combination information having one band entry even inSupportedBandCombinatonList to properly set a measurement capabilityparameter. When the UE generates the capability report message, the BCPof the BCPs for the band recorded in the n-th order insupportedBandListEUTRA, which includes one entry, sets the sequence ofthe BCPs to be recorded in the n-th order even inSupportedBandCombinationList. For example, because band X and band Y aresequentially recorded in supportedBandListEUTRA 501, theSupportedBandCombinationList 508 codes band X and band Y such that theBCP 510 including only band X and the BCP 515 including only band Y arethe first and second BCPs. If at least one BCP includes only band X, theBCP to which CA is not applied (that is, a bandwidth class is A) isdisposed first, and the BCP to which CA is applied is disposed after allthe single band BCPs to which CA is not applied are disposed. That is,among the BCPs 510 and 520 including only band X, the BCP 510 isdisposed in the first place and the BCP 520 is disposed in the nextplace of the BCP including only band Y.

In summary, when the UE performs a limited capability report, the entireSupportedBandListEUTRA of the UE may be reported without being limitedby the capability report restriction information.

If the eNB receives a UE CAPABILITY INFORMATION message from the UE instep 745, steps 750 to 760 are performed like steps 450 to 460.

When capability report restriction information 4 is used, the controlmessage of step 740 includes information on a band list that willrestrict report of capability (for example, only band 1, band 2, band 3,and band 4 are included in the capability report target list), andinformation on a carrier aggregation band combination including aspecific number of band combinations using the band list (for exampleinformation of a combination of band 3 and band 1 may be includedregarding a carrier aggregation band combination including X downlinks(three downlinks) and Y uplinks (for example, one uplink)).

If the UE receives a message of step 740 including the information, forexample, that only a band combination including one band (or band entry)to which carrier aggregation supported by the UE is not applied for band1, band 2, band 3, and band 4 and carrier aggregation band combinationinformation elements of all carrier aggregation band combinationsincluding N downlinks and M uplinks (N and M are integers equal to orlarger than 1), which includes three downlinks and one uplink may beincluded in the message of step 745 to be transmitted, and accordingly,the amount of transmitted information can be reduced.

In some embodiments of the present invention, a band combinationincluding one band (or band entry) and carrier aggregation bandcombinations including two downlinks and one uplink may be alwaysincluded regardless of carrier aggregation band combination information(“3” and “1” in the example) corresponding to the restricted specificnumber. That is, the carrier aggregation band combinations may beregarded as default band combinations included in the message of step745. The default band combinations correspond to one method of theembodiment, and a method of excluding a default band combination is alsopossible. In this case, only information on carrier aggregation bandcombinations of all the band combinations supported by the UE, amongband 1, band 2, band 3, and band 4, which include downlinks and uplinkscorresponding to the numbers indicated by the eNB is reported. Forexample, only the carrier aggregation band combination informationincluding three downlinks and one uplink may be reported.

The band combination including one band (or band entry) may be expressedby one downlink and one uplink (X=1, Y=1). In another method, if the Xand Y values are restricted by the eNB with X downlinks and Y uplinks,the UE may include information on band combinations including a carrieraggregation band combination corresponding to a subset of a carrieraggregation band combination and one band (or band entry) as well ascarrier aggregation band combinations including X downlinks and Yuplinks in the message of step 745. For example, in step 740, the eNBindicates only band 1, band 2, band 3, and band 4 as a capability reporttarget list and it is indicated that X is 3 and Y is 1, and it isassumed that the UE supports a band combination including one band (orband entry) and all carrier aggregation band combinations including allN downlinks and M uplinks (N and M are integers equal to or largerthan 1) for band 1, band 2, band 3, and band 5 (band 5 is not present inthe capability report target list indicated by the eNB). In addition tothe carrier aggregation band combinations including three downlinks andone uplink supporting band 1, band 2, and band 3, the UE includescarrier aggregation band combinations [2+1] including two downlinks andone uplink regarded as a subset of [3+1] carrier aggregation bandcombinations for band 1, band 2, and band 3 and band (or band entry)combinations including one downlink and one uplink.

Regardless of which of 1, 2, 3, and 4 is used as capability reportrestriction information, the amount of information of the bandcombinations supported by the UE may exceed a maximum value that may beinformed of by the message of step 745. In order to handle such a case,the capability report restriction information may be indicated inconsideration of a priority when the capability report restrictioninformation is indicated by the eNB through the message of step 740. Thepriority information may be indicated as explicit control information orindicated implicitly. As an example of the explicit control information,the capability report restriction information may be classified intogroups for the priorities and may be signaled. Meanwhile, as an exampleof implicit control information, the priorities may be implicitlysignaled in the arrangement sequence by arranging the capability reportrestriction information in the sequence from the highest priority to thelowest priority (or may be arranged in the sequence from the lowestpriority to the highest priority). If the number of band combinationsthat will be included in the message of step 745 exceeds a maximum valuethat can be accommodated in accordance with the capability reportrestriction information indicated by the message of step 740, it ispreferred that only those band combination information elements areincluded for the bands having a relatively higher priority until thementioned maximum value is reached.

Meanwhile, information that indicates a state in which band combinationsare included in the message of step 745 according to the capabilityreport restriction information indicated by the eNB but exceeds amaximum value so as not to include all the band combinations may beincluded in the message of step 745. When the indication information isincluded in the message received in step 745 and if there is a need forband combinations present other than the band combinations included inthe message received in step 745, the eNB may additionally requestinformation on additional support band combinations from the UE usingcapability report restriction information elements 1, 2, 3, and 4. FIG.8 is a diagram illustrating an example of capability report restrictioninformation according to a second embodiment of the present invention.

When the UE determines SupportedBandCombinationList when reporting arestricted capability, for the BCPs including only one band informationelement, the UE records all BCPs without being restricted by capabilityreport restriction information and for the BCPs including at least(preferably more than) one band information element, the UE records BCPsdetermined according to the capability report restriction information.

When the UE performs a restricted capability report, a newly generatedMeasParameters is used based on SupportedBandCombinationList andrestricted by the capability report restriction information rather thanMeasParameters generated based on the entireSupportedBandCombinationList of the UE.

For example, the UE supports, 805, band 1, band 2, band 3, and band 4,and supports, 810, a total of 12 band combinations. An IFNG thatindicates, 815, whether measurement gaps are necessary for bands of the12 band combinations is recorded in MeasParameters of the UE.

Band 1, band 2, band 3, and band 5 are indicated to the UE as the firstcapability report restriction information. The UE records information onall bands supported by the UE in supportedBandListEUTRA, the BCPsincluding one band are recorded in SupportedBandCombinationListaccording to the sequence recorded in supportedBandListEUTRA, and themeasurement capability information elements 820 for the BCPs are allrecorded.

The UE sequentially records with respect to BCPs including at least oneband the BCPs that satisfy the following condition inSupportedBandCombinationList.

<Condition>

The BCP corresponding to the band combination including at least oneband, for example, the UE that includes only bands of all E-UTRA bands,which are indicated by the first capability report restrictioninformation sequentially includes the BCPs corresponding to bandcombinations [1+2], [1+3], [1+2+3] in SupportedBandCombinationList, andincludes, 825, the BIs corresponding to the BCPs in MeasParameters.

That is, the UE generates a UE capability report message including 820and 825 and transmits the UE capability report message to the eNB.

Because the UE may not report a capability for all bands (in theexample, band 1, band 2, band 3, and band 5) indicated by the eNB (inthe example, the BCP for band 5 is not reported but the BCPs includingband 1, band 2, and band 3 are reported), and the UE may includeinformation regarding which bands the band combination information arerecorded for or indicating in the capability report message. That is, ifthe eNB indicates band 1, band 2, band 3, and band 5 as capabilityreport restriction information 1, the UE may include, in the capabilityreport message, information indicating that the bands considered by theUE in the band combination information are band 1, band 2, and band 3.That is, the frequency band list including some of capability reportrestriction information 1 may be included in the capability reportmessage as information that is separate from supportedBandListEUTRA.

The same principle is also applied when capability report restrictioninformation elements 2 and 3 are used. For example, if band combinations[1+3] and [1+5] are indicated as capability report restrictioninformation element 2, the UE generates a capability report messageincluding 820 and 830 and reports the generated message.

In order to prevent the eNB from requesting a capability report wheneverthe UE sets connection with the eNB, the UE may include information thatmay distinguish a case of reporting an entire capability from a case ofreporting some capabilities in the capability report message.

If capability information of the UE and information regarding whetherthe capability information is information on the entire capability orinformation on some capabilities may be recorded in the UE CAPABILITYINFO INDICATION message and transmitted to the MME, the MME may storethe transferred information. When the UE newly sets a connection later,the MME may include information regarding whether the information isinformation on the entire capability or information on some capabilitiesand capability information of the UE in the INITIAL CONTEXT SETUPREQUEST message and may transmit the message to the eNB. If thetransferred capability information is information on the entirecapability, the eNB does not transmit UE CAPABILITY ENQUIRY to the UE.If the transferred capability information is information on somecapabilities and band combination information desired by the eNB isomitted, the eNB generates UE CAPABILITY ENQUIRY and transmits UECAPABILITY ENQUIRY to the UE.

FIG. 9 is a flowchart illustrating an operation of a UE according to thesecond embodiment of the present invention.

Referring to FIG. 9, in step 905, when receiving the UE CAPABILITYENQUIRY message, the UE performs step 910 and identifies the RAT Typeincluded in the message.

If the RAT Type is set to EUTRA, the UE performs step 920, while if theRAT Type is not set to the EUTRA but another value, the UE performs step915. In step 915, the UE is operated according to the related art likein step 615. In step 920, the UE inspects whether capability reportrestriction information is recorded in the UE CAPABILITY ENQUIRYmessage, and if capability report restriction information is recorded,step 930 is performed, and if capability report restriction informationis not recorded, step 925 is performed.

In step 925, the UE records the entire capability in the UE CAPABILITYINFORMATION message and performs step 950.

In step 930, the UE records an entire capability insupportedBandListEUTRA. That is, the UE records all supported bands.

In step 935, the UE records an entire capability for a band combinationincluding a single band in SupportedBandCombinationList.

In step 940, the UE selectively records only a band combination selectedby the capability report restriction information for a band combinationincluding multiple bands in SupportedBandCombinationList.

In step 945, the UE records capabilities of the BCPs ofSupportedBandCombinationList and the BIs corresponding to the BCPs inwhich capability report restriction information is considered inmeasParameters.

The information on the recorded capability may be coded by ASN.1.

In step 950, the UE generates a UE CAPABILITY INFORMATION message thatrecorded the information recorded in steps 930 to 945 to transmit thegenerated UE CAPABILITY INFORMATION message to the eNB. Then, if theuser data (for example, an IP packet or a voice frame) that weregenerated first are present, the UE CAPABILITY INFORMATION message maybe transmitted ahead of the user data that were generated first.

FIG. 10 is a block diagram illustrating a configuration of a UEaccording to an embodiment of the present invention.

Referring to FIG. 10, the UE includes a transceiver 1005, a controller1010, a multiplexer and demultiplexer 1015, a control message processor1030, and at least one higher layer processor 1020 and 1025.

The transceiver 1005 receives data and a predetermined control signalthrough a downlink channel of a serving cell, and transmits data and apredetermined control signal through an uplink channel of the servingcell. In the case that a plurality of serving cells is set, the signaltransceiver 1005 transmits and receives data and a control signalthrough the plurality of serving cells.

The multiplexing and demultiplexing unit 1015 multiplexes data generatedby the higher layer processors 1020 and 1025 or the control messageprocessor 1030, or demultiplexes data received in the signal transceiver1005 to transmit the data to the suitable higher layer processors 1020and 1025 or the control message processor 1030.

The control message processor 1030 processes the control messagereceived from the eNB, and performs a necessary operation. Particularly,when receiving a control message such as the UE CAPABILITY ENQUIRY, thecontrol message processor 1030 analyzes contents of the control messageand performs a necessary operation, for example, generates and transmitsa UE CAPABILITY INFORMATION control message including the capabilityinformation of the UE to the subordinate layers 1015 and 1005. Thecontrol message processor 1030 may perform an operation corresponding tothe terminal operation illustrated in FIGS. 4 to 9 and a necessarycontrol operation.

The higher layer processors 1020 and 1025 may be configured according toeach service, which processes and transmits data generated by a userservice such as File Transfer Protocol (FTP) or Voice over InternetProtocol (VoIP) to the multiplexing and demultiplexing unit 1015 orprocesses and transmits data received from the multiplexing anddemultiplexing unit 1015 to a higher layer service application.

The controller 1010 identifies a scheduling instruction received throughthe signal transceiver 1005, for example, backward grants, and controlsthe signal transceiver 1005 and the multiplexing and demultiplexing unit1015 so as to perform a backward transmission through a suitabletransmission resource at an appropriate time point.

Although FIG. 10 illustrates that the transceiver 1005, the controller1010, the multiplexer and demultiplexer 1015, the control messageprocessor 1030, and the higher layer processor 1020 and 1025 areconfigured in separate blocks and the blocks perform differentfunctions, it is only for convenience of description and the functionsare not classified. For example, the controller 1010 may generate a UECAPABILITY INFORMATION message including capability information of theUE, and transmit the generated UE CAPABILITY INFORMATION message to theeNB. The capability information of the UE may include informationregarding one or more band combinations supported by the UE and whetherTime Division Duplexing-Frequency Division Duplexing Carrier Aggregation(TDD-FDD CA) is supported for the band combinations. Here, thecapability information of the UE may further include at least one of ameasurement capability parameter (MeasParameter) of the UE, PCell moderelated information (PCellCapability), and release information(accessStratumRelease) of the UE. The PCell mode related information mayinclude at least one of information on whether the UE supports TDD PCellor information on whether the UE supports FDD PCell. The controller 1010may receive a UE CAPABILITY ENQUIRY message that instructs a reportingof capability information of the UE from the eNB, identifying a RadioAccess Technology type contained in the UE CAPABILITY ENQUIRY message,and determine terminal capability information that will be contained inthe UE CAPABILITY INFORMATION message according to the identified RATtype. The controller 1010 may transmit the UE CAPABILITY INFORMATIONmessage ahead of user data generated before the UE CAPABILITYINFORMATION message is generated. The measurement capability parameterof the UE includes BandCombinationParameters (BCPs) and band information(BandInfoEUTRAs) (BIs), and the number of the BCPs and the number of BIsare the same and the BCP may have corresponding BIs. The capabilityinformation of the UE may further include information regarding whetherInter-Operability Tests (IOTs) for the PCellCapabilitys are completedfor TDD-FDD CA band combinations.

FIG. 11 is a block diagram illustrating a configuration of the eNBaccording to an embodiment of the present invention, and includes atransceiver 1105, a controller 1110, a multiplexer and demultiplexer1120, a control message processor 1135, various higher layer processors1125 and 1130, and a scheduler 1115.

Referring to FIG. 11, the transceiver 1105 transmits data and apredetermined control signal to a downlink carrier and receives data anda predetermined control signal to an uplink carrier. In the case that aplurality of carriers are set, the signal transceiver 1105 transmits andreceives data and a control signal through the plurality of carriers.

The multiplexing and demultiplexing unit 1120 multiplexes data generatedby the higher layer processors 1125 and 1130 or the control messageprocessor 1135, or demultiplexes data received in the signal transceiver1105 to transmit the data to the suitable higher layer processors 1125and 1130, the control message processor 1135, or the controller 1110.The control message processor 1135 processes a control messagetransmitted by the UE to transfer necessary information to thecontroller 1110, or generates a control message that will be transferredto the UE under the control of the controller 1110 to transfer thecontrol message to the lower layer.

The higher layer processors 1125 and 1130 may be constituted for eachbearer, which constitutes the RLC PDU of data received from the S-GW oranother eNB to transmit the RLC PDU to the multiplexing anddemultiplexing unit 1120, or constitutes the PDCP Service Data Unit(SDU) of the RLC PDU received from the multiplexing and demultiplexingunit 1120 to transmit the PDCP SDU to the S-GW or another eNB.

The scheduler 1115 allocates a transmission resource to the UE at asuitable time point considering a buffer state, a channel state, and thelike of the UE, and enables the signal transceiver 1105 to process asignal received from the UE, or to transmit a signal to the UE.

The controller 1110 instructs the control message processor 1135 togenerate and transmit a suitable RRC control message to the UE, orperforms necessary operations by using control information processed bythe control message processor 1135. For example, an operationcorresponding to the terminal operation illustrated in FIGS. 4 to 9 anda necessary control operation may be performed.

Although FIG. 11 illustrates that the transceiver 1105, the controller1110, the multiplexer and demultiplexer 1120, the control messageprocessor 1135, and the higher layer processor 1125 and 1130 areconfigured in separate blocks and the blocks perform differentfunctions, it is only for convenience of description and the functionsare not classified. For example, the controller 1110 may transmit a UECAPABILITY ENQUIRY message that instructs a reporting of capabilityinformation of the UE to the UE, and receive a UE CAPABILITY INFORMATIONmessage including the capability information of the UE from the UE. TheUE CAPABILITY INFORMATION message may include information regarding oneor more band combinations supported by the UE and whether Time DivisionDuplexing-Frequency Division Duplexing Carrier Aggregation (TDD-FDD CA)is supported for the supported band combinations. If the UE CAPABILITYINFORMATION message is received, the controller 1110 transmits a UEcapability information indication (UE CAPABILITY INFO INDICATION)message including the capability information to a Mobility ManagementEntity (MME). The capability information of the UE CAPABILITYINFORMATION message may further include at least one of a measurementcapability parameter (MeasParameter) of the UE, PCell mode relatedinformation (PCellCapability), and release information(accessStratumRelease) of the UE. When the capability information of theUE CAPABILITY INFORMATION message does not include PCell mode relatedinformation, the controller 1110 may determine whether the UE supportsTDD-FDD CA based on release information of the UE contained in thecapability information of the UE CAPABILITY INFORMATION message. The UECAPABILITY ENQUIRY message may include information that instructs the UEto report one of capability information related to a frequency bandactually used by the UE, capability information related to a frequencyband combination actually used by the UE, capability information relatedto a frequency band combination and a bandwidth class actually used bythe UE.

In accordance with further embodiments of the present invention, amethod may include transmitting capability information of a UserEquipment (UE) to an evolved Node B (eNB) by the UE by means ofgenerating a UE CAPABILITY INFORMATION message including capabilityinformation of the UE; and transmitting the UE CAPABILITY INFORMATIONmessage to the eNB, wherein the capability information of the UEincludes information regarding one or more band combinations supportedby the UE and whether Time Division Duplexing-Frequency DivisionDuplexing Carrier Aggregation (TDD-FDD CA) is supported for the bandcombinations.

A corresponding UE for transmitting capability information of the UE toan eNB can include a transceiver configured to transmit and recievesignals to and from the eNB; and a controller configured to generate aUE CAPABILITY INFORMATION message including capability information ofthe UE, and transmitting the generated UE CAPABILITY INFORMATION messageto the eNB, wherein the capability information of the UE includesinformation regarding one or more band combinations supported by the UEand whether Time Division Duplexing-Frequency Division Duplexing CarrierAggregation (TDD-FDD CA) is supported for the band combinations.

In accordance with further embodiments of the present invention, amethod may include receiving capability information of a user equipmentfrom a UE by an eNB by means of transmitting a UE CAPABILITY ENQUIRYmessage that indicates report of capability information of the UE to theUE; and receiving a UE CAPABILITY INFORMATION message includingcapability information of the UE from the UE, wherein the UE CAPABILITYINFORMATION message of the UE includes information regarding one or moreband combinations supported by the UE and whether Time DivisionDuplexing-Frequency Division Duplexing Carrier Aggregation (TDD-FDD CA)is supported for the band combinations.

The method may include transmitting a UE CAPABILITY ENQUIRY message thatindicates report of capability information of the UE to the UE.

A corresponding eNB for receiving capability information of a UE fromthe UE can include a transceiver configured to transmit and receivesignals to and from the UE; and a controller configured to transmit a UECAPABILITY ENQUIRY message that indicates report of capabilityinformation of the UE to the UE and to recieve a UE CAPABILITYINFORMATION message including the capability information of the UE fromthe UE, wherein the UE CAPABILITY INFORMATION message includesinformation regarding one or more band combinations supported by the UEand whether Time Division Duplexing-Frequency Division Duplexing CarrierAggregation (TDD-FDD CA) is supported for the band combinations.

The eNB may further include a controller that is configured forgenerating a UE CAPABILITY ENQUIRY message that indicates the UE toreport capability information of the UE and the transceiver may beconfigured for transmitting to the UE the UE CAPABILITY ENQUIRY message.

Although specific exemplary embodiments have been described in thedetailed description of the present disclosure, various change andmodifications may be made without departing from the scope of thepresent disclosure. Therefore, the scope of the present invention issolely defined by the appended claims.

What is claimed is:
 1. A method for transmitting capability informationby a terminal in a communication system, the method comprising:receiving, from a base station, a first message including firstinformation that requests at least one frequency band supported by theterminal and second information on a requested maximum bandwidth;determining at least one band combination supported by the terminalbased on the first information and the second information; andtransmitting, to the base station, a second message in response to thefirst message, the second message including the at least one bandcombination supported by the terminal.
 2. The method of claim 1, whereineach band in the at least one band combination does not exceed therequested maximum bandwidth.
 3. The method of claim 1, wherein the atleast one band combination in the second message is prioritized based onthe first information included in the first message.
 4. The method ofclaim 1, wherein the first message further comprises third informationon a requested radio access technology.
 5. A method for receivingcapability information by a base station, the method comprising:generating a first message including first information that requests atleast one frequency band supported by a terminal and second informationon a requested maximum bandwidth; transmitting, to the terminal, thefirst message; and receiving, from the terminal, a second message inresponse to the first message, the second message including at least oneband combination supported by the terminal determined based on the firstinformation and the second information.
 6. The method of claim 5,wherein each band in the at least one band combination does not exceedthe requested maximum bandwidth.
 7. The method of claim 5, wherein theat least one band combination in the second message is prioritized basedon the first information included in the first message.
 8. The method ofclaim 5, wherein the first message further comprises third informationon a requested radio access technology.
 9. A terminal for transmittingcapability information in a communication system, the terminalcomprising: a transceiver; and a controller coupled with the transceiverand configured to: receive, from a base station, a first messageincluding first information that requests at least one frequency bandsupported by the terminal and second information on a requested maximumbandwidth, determine at least one band combination supported by theterminal based on the first information and the second information, andtransmit, to the base station, the second message in response to thefirst message, the second message including the at least one bandcombination supported by the terminal.
 10. The terminal of claim 9,wherein each band in the at least one band combination does not exceedthe requested maximum bandwidth.
 11. The terminal of claim 9, whereinthe at least one band combination in the second message is prioritizedbased on the first information included in the first message.
 12. Theterminal of claim 9, wherein the first message further comprises thirdinformation on a requested radio access technology.
 13. A base stationfor receiving capability information, the base station comprising: atransceiver; and a controller coupled with the transceiver andconfigured to: generate a first message including first information thatrequests at least one frequency band supported by a terminal and secondinformation on a requested maximum bandwidth, transmit the first messageto the terminal, and receive, from the terminal, a second message inresponse to the first message, the second message including at least oneband combination supported by the terminal determined based on the firstinformation and the second information.
 14. The base station of claim13, wherein each band in the at least one band combination does notexceed the requested maximum bandwidth.
 15. The base station of claim13, wherein the at least one band combination in the second message isprioritized based on the first information included in the firstmessage.
 16. The base station of claim 13, wherein the first messagefurther comprises third information on a requested radio accesstechnology.